Heat exchanger formed by modules

ABSTRACT

A HEAT EXCHANGER IS FORMED OF HEAT EXCHANGER UNITS WHICH EACH HAVE A SECTION OF THE HEADER AND A POROUS MATERIAL WITH A MULTIPLICITY OF TUBES EMBEDDED THEREIN WITH THE TUBES COMMUNICATING WITH THE HEADER SECTION. THE UNITS ARE ASSEMBLED AND JOINED TOGETHER TO FORM HEADERS.

United States Patent HEAT EXCHANGER FORMED BY MODULES 5 Claims, 11Drawing Figs,

U.S..Cl 165/158, 29/157.4,165/159, 165/164,165/175 Int. Cl F281 9/02,F28f1/10 Field Search 165/175,

[56] References Cited UNITED STATES PATENTS 3,289.756 12/1966 Jaeger165/180X 3,415,316 12/1968 BurneetalM 165/164 FOREIGN PATENTS 647,6757/1928 France 165/164 701,144 1/1931 France 165/158 882,095 7/1953Germany 165/160 144,659 1/1952 Australia 165/158 Primary ExaminerA1bertW. Davis, Jr. Anorneys- Henry W. Cummings, Robert H. Bachman, Arthur N.Krein, Richard S. Strickler and George .1. Koeser ABSTRACT: A heatexchanger is formed of heat exchanger units which each have a section ofthe header and a porous material with a multiplicity of tubes embeddedtherein with the tubes communicating with the header section. The unitsare assembled and joined together to form headers.

PATENTEDJUNZSIQYI cal-587,732

SHEET 1 0F 3 I INVENTOR; FREDERICK/1. BURNE ATTORNEY PATENTED JUN28 19mSHEET 2 UF 3 INVEN'I 0R: FREDERICK A. BU/PNE ATTORNEY PATENTEU JunzsI971 SHEET 3 BF 3 INVENTOR: FREDERICK/1. BURNE III/l ATTORNEY HEATEXCHANGER FORMED BY MODULES This application is a division of copendingapplication Ser. No. 692,913, filed Dec. 22, 1967, now abandoned.

This invention relates to heat exchangers.

In particular, it relates to the type of heat exchanger described inU.S. Pat. No. 3,289,756 issued to U. R. .laeger. In this patent a heatexchanger is described in which a plurality of tubes are conductivelybonded to a body of pervious material. One heat exchange medium passesthrough the tubes while another heat exchange medium passes radiallythrough the pervious material providing extended surface and anefficient, compact heat exchanger.

In US. application SerfNo. 629,954 of Burne and Valyi, filed Apr. ll,I967 and assigned to the same assignee as the present invention, modularunits having a tube conductively bonded to a layer of porous materialare described. The invention in Ser. No. 629,954 allows the productionof units of extended length due to the modular construction.

The object of the present invention is to allow the production ofmodular units of indefinite length, and will, furthermore, allow greatquantities of the heat exchange medium to be heated or cooled and passedthrough the heat exchanger with very low pressure drop.

In the drawings, FIG. 1 is a section along the lines 1-1 in FIG. 2.

FIG. 2 is a section along the lines 2-2 in FIG. 1.

FIG. 3 is a partial end view of header 20.

FIG. 4 is a partial view of the header 30.

FIGS. 5A and 5B are front and side views respectively of the header 40.

FIGS. 6A and 6B are front and side views of the headers 50.

FIG. 7 is a sectional view. of another embodiment of the presentinvention.

' FIG. 8 is a sectional view along the lines 8-8 in FIG. 7.

FIG. 9 is an end view of header 500.

In FIGS. 1 and 2, a heat exchanger is shown in which a plurality oftubes 90 are conductively bonded to porous material 80, as shown in FIG.2, a plurality of these tubes bonded to porous material constitutemodule units 100. In addition, the modular units 100 contain a centerconduit I0. A plurality of these units I are placed within a shell 70.However, before placement in the shell, the headers 40 and 50, as shownin FIGS. A, 53, 6A and 6B are attached to each end of the units 100.

The header 40 has a plurality of openings M to receive the tubes 90 foreach unit. Additionally, there is an opening 42 which cooperates withcavity 10. As can be seen from FIG. I, there is a portion 91 of thetubes 90 which does not have porous material 80 conductively bondedthereto. The headers 40 are placed upon the units 100 and the layer ofporous material 80, the portions 91 of tubes 90 extending through theopenings 41, and the openings 42 lining up with the conduits 10 in theunits 100'.

It can also be seen from FIG. I that there is a second end portion 92 oftubes 90 which does not have a layer of porous material conductivelybonded thereto. The headers 50 having openings 51 are placed upon thisend of the units I00, with the end portion 92 of the tubes passingthrough openings 51. However, it is apparent that header 50 differs fromheader 40 in that there is no center opening in header 50.

As can also be seen in FIG. I, the tube end portions 91 of the units 100are sealingly received, such as by welding, in a large header 20. Headeris'shown in a partial end view in FIG. 3. This header has a plurality ofopenings 21, 22, 23, 24 and 25 for the tubes from each of the units 101,I02, I03, I04, and 105 shown in FIG. 2. It is thus apparent that theheader 20 receives all the tube end portions from all the units in theheat exchanger.

However, it is emphasized that, if desired,'the end portions 91 could bereceived in small headers such as 50, which small headers wouldthen bereceived in headers such as shown in FIG. 4 and appropriately sealedthereto.

As also can be seen from FIG. I inwardly from header 20, a 9

on each of the units. Thus, as can be seen from FIG. 4, the header 30has a plurality of openings 31, 32, 33, 34 and 35 corresponding to theheaders 40, shown in FIGS. 5A and 58.

There is provided at the other end of theheat exchanger a second header60, having the same shape as the header 30, which receives thecorresponding end headers 50. Thus, each of the units 101, I02, 103, 104and 105 is received in a corresponding end header 50 having theconfiguration shown in FIGS. 6A and 6B. The headers 50, in turn, fitinto the large header 60 in the same way that the headers 40 arereceived in header 30.

The shell 70 has end plates 71 which fit on either end of the heatexchanger. Also, there are two inlet conduits 72 and 73, and outletconduits 74 and 75 as shown in FIG. 1. Obviously, additional inlet andoutlet conduits could be provided, if

desired. I

The header plate 71 together with header 20 define an inlet chamber 11which communicates with inlet conduit 72. Similarly, headers 20 and 30define a second inlet chamber 12 which communicates with inlet 73. Inlike manner, end plate 7 I and header 60 define an outlet chamber 13which communicates with outlet conduit 75. Outlet conduit 74communicates with outlet chamber 14 defined by shell 70 and headers 30and 60.

Thus, in an exemplary embodiment of the present invention, water fromany convenient source is introduced into one or more conduits 73. Thewater then passes through chamber 11 into end portion 91 of tubes 90,through headers 20 and 30 and 60, into exit chamber 13, and out throughone or more conduits 75, having absorbed or rejected heat during thepassage through tubes 90.

At the time, a heat exchange medium to be heated or cooled, for example,oil to be cooled, is introduced through one or more conduits 73 intoinlet chamber 12. From there, it passes into center conduit 10 throughopenings 42 in the headers 40. From the chamber 10 the oil passesradially outwardly through porous material 80. During its radial passagethrough porous material 80, the oil is in heat exchange relation withthe heat exchange medium (i.e., cooling water) passing through tubes andloses or gains heat by way of the porous matrix and tube wall. After theoil exits from porous material 80, it passes into exit chambers 10and/or 16 or 17 shown in FIG. 2, and is collected in chamber 14. Fromthere it exits through one or more conduits 74. From there, the oil caneither be additionally cooled or put back in service. Obviously, otherheat exchange media, including gases, could be process, instead of waterand oil.

According to one method of assembling the heat exchanger of FIG. 1, thetubes 90 are first placed in headers 40 and 50. A brazing compound maybe placed on the tubes as they are fitted into the headers. The unitswith headers 40 and 50 in place are next fitted with a screen or core todefine the cavity 10. This assembly is placed in a mold and shot, alsoparticulate material such as containing brazing material is poured intothe mold. This assembly is then placed in a brazing furnace and heatedto appropriate temperatures and time for the particularshot material toform pervious layers 80.

The units are then removed from the furnace and if a core is used todefine channel 10, the core is removed at this point. Of course, if ascreen is used, it need not be removed. I

The units are next fitted into the larger headers 20, 30, and 60. Eithera small header or the tube ends 93 are received in header 20. Header 30receives headers 40. Headers 60 receive headers 50. Appropriate sealsare provided at these points. After sealing, for instance, by brazing orwelding the entire core is placed within a shell 70 and the headers 20,30 and.60. scaled to shell 70, for example, by brazing or welding.Appropriate conduits such as 72, 73, 74 and 75 which have already beenprovided on the shell 70 may then be appropriately connected.

FIGS. 7 and 8 show another embodiment of the present invention. As seenin this embodiment, a plurality of tubes 900 are conductively bonded toa body of porous material 800.

Thus, the heat exchange portions 1010, 1020 and 1040 are very similar tothose in FIGS. 1 and 2. However, the units 430, 440, 450 and 460 aremade up of the cores together with pie section headers. Thus, theheaders 200, 500 and 300 shown in FIG. 8 are made up of pie quartersections. As can be seen from the double section in FIG. 7, quartersections 230 and 260 are shown defining half of header 200, whilequarter sections 540 and 550 define half of header 500. Header 500 isshown more clearly in FIG. 9 in which all portions of header 500,quarter sections 530, 540, 550 and 560 appear. The pie sections are heldtogether by welds 270 and $70.

In order to form the units shown in FIGS. 7 and 8, the tubes 900 areplaced in the quarter section headers. Appropriate sealing means, forexample, brazing material, is provided on the tubes. The quartersections with the tubes in place are then placed in a mold which definesthe desired cross section of the portions 1010, 1020, 1030 and 1040,with either a tubular screen or core to define the center 100. Shotmaterial for forming the porous body 800 together with a brazingcompound to bond the shot together and to the quarter section headersare poured into the mold. After the shot and brazing material are placedin the mold, the quarter section units are placed in a brazing furnaceand heated to the appropriate temperature and time for the particularbrazing material and shot material. The porous body is thus formed andthe porous body is bonded to the pie section headers. After removal fromthe furnace, the cores are removed from the units. If a screen is used,of course, it is not necessary to remove the screen. This results inquarter section units such as 430, 440, 450 and 460.

In order to assemble an entire heat exchanger core, the units are merelywelded together, as at 270 and 570. Welding is also carried out todefine header 300. The so-welded together core is then slid into shell'700 and is soldered or brazed in place. The shell ends 710 and 720 canthen be attached to the shell 700 in an appropriate manner, such as bybrazing or by welding.

The heat exchanger operates as follows. One heat exchange medium (forexample, water) is introduced at 720, passes through tubes 900 andleaves through chamber I30 through outlet 750. A heat exchange medium tobe heated or cooled (for example, oil) is introduced at 730. It passesradially inwardly to center 100 in the chamber 120. During its passagetherethrough, heat is exchanged with the heat exchange medium and passesthrough tube 900. The second heat exchange medium passes through header500 through opening 510 therein and into chamber 140. As the second heatexchange medium passes radially outwardly from the center 100, it isagain in heat exchange relation with the first heat exchange mediumpassing through tubes 900. The second heat exchange medium collects. inthe outer portion of chamber 140 and leaves through conduit 740.

It is apparent that this is a double pass unit because heat is exchangedbetween the second heat exchange medium and first heat exchange mediumduring the passage inwardly to channel 100 in chamber 120 and during theoutward passage from channel 100 in chamber 140.

It is also apparent that the parallel flow which takes place in such aheat exchanger (the flow through units 430 is parallel to the flowthrough units 440 and 450, etc.) provides for a low pressure drop.

The method of sealing the tubes to the small headers, the small headersto the large headers, and the headers to the shell in addition tobrazing, could be done by an O-ring seal in an substantially all of themedium to be heated or cooled is in heat exchange relationship with theheat exchange medium passing through the tubes.

Furthermore, the units can be manufactured in long lengths if desired.The cross section size of each unit is small enough to so that uniformbrazing of the porous material can be obtained. Thus, the size of thisheat exchanger is not limited by the brazing operation.

It is to be understood that the invention is not limited to theillustrations described and shown herein which are deemed to be merelyillustrative of the best modes of carrying out the invention, and whichare susceptible of modifications of forms, size, arrangement of partsand detail of operation, but rather is intended to encompass all suchmodifications which are within the spirit and scope of the invention asset forth in the appended claims.

I claim: v

l. A heat exchanger comprising:

a heat exchange core which is characterized in that it contains aplurality of units, each unit comprising a porous body having acentrally located conduit therein, a plurality of tubes radiallydisposed about said conduit, said tubes being conductively bonded withinsaid porous body, each unit further having at least one pie-shapedheader section which communicates with said tubes, said units beingassembled into said heat exchange core with said header sections beinginterfittingly connected to define a complete header;

means communicating with said tubes for passing a first heat exchangemedium through said tubes;

means communicating with said tubes for collecting said first heatexchange medium after it is passed through said tubes;

means communicating with said porous body for passing a portion of asecond heat exchange medium through said porous body of each of saidunits in a general radial direction; and

means communicating with said porous body for collecting said secondheat exchange medium after it has passed through said porous body.

2. A heat exchanger according to claim 1 wherein said means for passingsaid second heat exchange medium through said porous body comprises afirst means for passing said second heat exchange medium through saidporous body in a general radial direction into said centrally locatedconduit and a second means for passing said second heat exchange mediumout from said conduit through said porous body in a general radialdirection.

3. A heat exchanger according to claim 1 wherein said header sectionsare pie-shaped.

4. A heat exchanger according to claim 1 wherein said header sectionsare connected by being welded together.

5. A heat exchanger according to claim 1 wherein said.

header sections are connected by being brazed together.

